This invention relates to a communication apparatus.
The volume of the traffic transported between servers or terminals is not generally constant and sometimes surges to cause instantaneous overloading traffic (burst traffic). Packet communication apparatuses that receive such burst traffic for the CPU retain packets in the reception buffer and gradually output the packets from the buffer to prevent packet loss. However, when the burst traffic exceeds the capacity of the communication apparatus, a congestion incident occurs to cause packet loss.
The recent advancement in the performance of servers, terminals, and communication apparatuses raises the possibility of generation of such overloading traffic beyond expectation or traffic caused by evil activities such as an attack. When the volume of the burst traffic is too large, a communication apparatus cannot retain the packets in the buffer, which could cause packet loss and further, increase congestion incidents that disturb the normal operation.
Under the circumstances where network users are increasing, service providers make a single network apparatus accommodate a larger number of users in order to fully utilize the limited resources in providing the service. This is increasing cases where locating the traffic responsible for congestion in a communication apparatus is found difficult.
Congestion in a network apparatus disturbs stable operation of the network. It is desirable to prevent occurrence of congestion and if congestion occurs, speedily locate the responsible traffic and take measures to stabilize the network.
JP 2011-142535 A discloses a packet relay apparatus configured to, when burst traffic causes a packet to overflow or to be ready to overflow from a queue, mirror only the packets to be accumulated in that queue.